I'm cooking at 86F this summer. Clutch #1 pipped at day 66, clutch #2 at day 69. Clutch #3 is on day 63, and is only just starting to dimple.
When the clutch falls apart, you'll know you're a few days away. And I can't believe I'm about to say "it's safe to cut", but once they fall apart, it probably it is.